
class calculator:
    def __init__(self):
        self.a = 0
        self.b = 0
    def add(self, a, b):
        return a + b
    def sub(self, a, b):
        return a - b
    def mul(self, a, b):
        return a * b
    def div(self, a, b):
        return a / b
p1 = calculator()
p1.add(1,2)
print(p1.add(1,2))